I’m beginning to wonder just how seriously some people take things like NDAs and industry secrets. Take for instance this screenshot that was recently shown on G4. I highly doubt that Harmonix wanted this to be seen, as it lists 11 tracks in Rock Band 2, 9 of which have not been announced. Of course I harbor no feeling of remorse for passing along the info to you guys.
One thing you should keep in mind is that Harmonix is constantly changing which tracks are going to be included for DLC (I would imagine the same holds true for the songs included on the RB2 disc). I wouldn’t be surprised if a few of these didn’t make the cut.